Imam Jafar bin Muhammad al Sadiq advised the believers to switch on lights in the house before sunset, as according to the Holy Prophet it is makru (undesirable) to enter a dark house, and at the time of turning on the lights recite the following dua'a.

[ O our Allah, let light illuminate our path when we walk among human beings. Do not keep us away from Your light on the day of judgement. Let there be light for us, because You are light. There is no God save You.]